Downhole tubular strings, such as drill strings, comprise connectors that are subjected to torque as the tubular members of the strings are manipulated. Conventional connectors that do not have a high enough torque capacity may be susceptible to failure. Further, some conventional connectors require precision machining that is costly and prone to inaccuracies in production. Using conventional manufacturing techniques, it can be difficult, if not impossible, to achieve sufficient torque capacity without increasing the size of the connector.